﻿/*Copyright (c) 2015, Nordic Semiconductor ASA
 *
 *Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
 *
 *1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
 *
 *2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other 
 *materials provided with the distribution.
 *
 *3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific 
 *prior written permission.
 *
 *THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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using Common.Service.ApplicationException;
using Common.Utility;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Windows.Devices.Bluetooth.GenericAttributeProfile;

namespace Common.Service.GattService
{
	public interface IUARTService : IGattService
	{
		bool IsServiceStarted { get; }
		Task<bool> Start(GattDeviceService uARTService);
		Task<bool> SendPeer(string text);
		event Common.Service.GattService.UARTService.EchoReceivedHandler EchoReceived;
		void Stop();
	}

	public class UARTService : IUARTService

	{
		public IRXCharacteristic IRXCharacteristic;
		public ITXCharacteristic ITXCharacteristic;

		#region Events
		public delegate void EchoReceivedHandler(string echo);
		public event EchoReceivedHandler EchoReceived;
		#endregion

		public UARTService(IRXCharacteristic rxCharacteristic, ITXCharacteristic txCharacteristic)
		{
			this.IRXCharacteristic = rxCharacteristic;
			this.ITXCharacteristic = txCharacteristic;
		}

		public async Task<bool> Start(GattDeviceService uARTService)
		{
			if (uARTService == null || uARTService.Uuid != ToolboxIdentifications.GattServiceUuids.Nordic_UART)
			{
				iSServiceStarted = false;
				return iSServiceStarted;
			}
			else
			{
				UARTGattService = uARTService;
				rxCharacteristic = this.UARTGattService.GetCharacteristics(ToolboxIdentifications.GattCharacteristicsUuid.RX).FirstOrDefault();
				iSServiceStarted = await EnableRXNotification();
				return iSServiceStarted;
			}
		}

		public async Task<bool> SendPeer(string text)
		{
			try
			{
				if (!iSServiceStarted || text == null)
					return false;
				var txCharacteristic = this.UARTGattService.GetCharacteristics(ToolboxIdentifications.GattCharacteristicsUuid.TX).FirstOrDefault();
				var buffer = IRXCharacteristic.TalkTo(text);
				await txCharacteristic.WriteValueAsync(buffer);
				return true;
			}
			catch (ApplicationArgumentException e)
			{
				// Buffer size too big
				return false;
			}
			catch (Exception e)
			{
				return false;
			}
		}

		private async Task<bool> EnableRXNotification() 
		{
			bool iSEnabled = false;
			if (rxCharacteristic != null)
			{
				rxCharacteristic.ValueChanged += rxCharacteristic_ValueChanged;
				var currentStatus = await rxCharacteristic.ReadClientCharacteristicConfigurationDescriptorAsync();
				if (currentStatus.ClientCharacteristicConfigurationDescriptor == GattClientCharacteristicConfigurationDescriptorValue.Notify)
					return iSEnabled = true;
				else
				{
					var result = await rxCharacteristic.WriteClientCharacteristicConfigurationDescriptorAsync(GattClientCharacteristicConfigurationDescriptorValue.Notify);
					return iSEnabled = true;
				}
			}
			return iSEnabled;
		}

		void rxCharacteristic_ValueChanged(GattCharacteristic sender, GattValueChangedEventArgs args)
		{
			string result = File.ToString(args.CharacteristicValue);
			if (EchoReceived != null)
				EchoReceived(result);
		}

		public string Name
		{
			get
			{
				return ToolboxIdentifications.GattServiceNames.NORDIC_UART;
			}
		}

		public void Stop() 
		{
			rxCharacteristic.ValueChanged -= rxCharacteristic_ValueChanged;
		}

		private bool iSServiceStarted = false;
		public bool IsServiceStarted 
		{ 
			get
			{
				return iSServiceStarted;
			}
		}
		private GattDeviceService UARTGattService { get; set; }

		public GattCharacteristic rxCharacteristic { get; set; }
	}
}
